Preparation and Formation Mechanism of Renewable Lignin Hollow Nanospheres with a Single Hole by Self-Assembly
Preparation and Formation Mechanism of Renewable Lignin Hollow Nanospheres with a Single Hole by Self-Assembly
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DOI：
10.1021/acssuschemeng.6b02585
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发表时间：
2017-03-01
影响因子：
8.4
通讯作者：
Chu, Fuxiang
中科院分区：
文献类型：
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作者：
Xiong, Fuquan;Han, Yanming;Chu, Fuxiang
将生物炼制过程中的副产物木质素酶解产物溶解于四氢呋喃中，然后滴加去离子水，通过简单的自组装方法制备了具有单一孔洞的木质素中空纳米球。探讨了木质素空心纳米球的形成机理和结构特征。结果表明，由于四氢呋喃对自组装行为的影响，纳米球呈现中空结构。基于π-π相互作用，通过层层自组装的方法，从外到内形成疏水的外表面和亲水的内表面。木质素空心纳米球的制备过程中，木质素的化学结构没有产生明显的变化。随着木质素初始浓度的增加，纳米球的直径和壳壁厚度增加，而纳米球的单孔直径、比表面积和孔体积减小。在设定的浓度范围内，木质素初始浓度为0.5 mg/mL时，比表面积达到最大值（25.4 m2 g-1）。提高搅拌速度或水的滴加速度，导致空心纳米球的直径减小。此外，在15天后没有观察到纳米球的平均直径的明显变化，并且纳米球分散体在3.5和12之间的pH值下是稳定的。具有单一孔的木质素空心纳米球为木质素的增值利用提供了新的途径，并将提高生物炼制的可行性。
Lignin hollow nanospheres with a single hole were prepared through a straightforward self-assembly method, which included dissolving enzymatic hydrolysis lignin, a byproduct derived from biorefinery, in tetrahydrofuran and afterward dropping deionized water to the lignin/tetrahy-drofuran solution. The formation mechanism and structural characteristics of the lignin hollow nanospheres were explored. The results indicated that the nanospheres exhibited hollow structure due to the effect of tetrahydrofuran on the self assembly behavior. Hydrophobic outside surface and hydrophilic internal surface were formed via layer-by-layer self-assembly method from outside to inside based on pi-pi interactions. The chemical structure of lignin did not produce a significant change in the preparation process of lignin hollow nanospheres. With increasing of initial lignin concentration, the diameter of the nanospheres and the thickness of shell wall increased, while the diameter of the single hole, the surface area, and the pore volume of the nanospheres decreased. The surface area reached the maximum value (25.4 m(2) g(-1)) at an initial lignin concentration of 0.5 mg/mL in setting concentration range. Increasing the stirring speed or dropping speed of water resulted in a decrease of the diameter of the hollow nanospheres. Moreover, an apparent change of the average diameter of the nanospheres was not observed after 15 days, and the nanosphere dispersions were stable at pH values between 3.5 and 12. The lignin hollow nanospheres with a single hole offer a novel route for a value-added utilization of lignin and would improve the biorefinery viability.